The present invention relates to wiring accessories, and more particularly to grommets and corresponding grommet installation tools and methods.
Electronic devices typically have panels, wall structures, compartments, or housings made of, e.g., metallic, plastic, sheet-like material(s). Often, conductors have to be routed through holes in such panels in order to electrically connect various components to each other or to auxiliary components. The perimeter edges of such panel holes tend to be rather sharp and may cut, abrade, or otherwise damage conductors extending therethrough. Accordingly, grommets are often installed concentrically in panel holes for preventing the conductors from contacting the sharp perimeter edges of the panel holes.
Grommets are often made from resilient, e.g., elastomeric, materials. The flexibility and deformability of such materials may accommodate or absorb some transverse pulling-type forces applied to conductors extending through a grommet and also may facilitate installation of grommets. In other words, the physical characteristics of some grommets allow them to be squeezed or folded down as they are inserted into the panel hole. When suitably positioned in the panel hole, the grommet is released and it unfolds or otherwise restores to its original configuration, locking it into or against the perimeter edge of the panel hole.
However, some grommets are relatively less flexible and require more effort to install. At times, installing such relatively less flexible grommets requires following detailed procedures or installation protocol set forth by a grommet manufacturer. Such relatively less flexible grommets are often implemented as sealed or liquid-tight configurations.
Liquid-tight characteristics of such liquid-tight grommets are achieved by providing (i) sealed interfaces between the grommets and panel holes, and (ii) sealed interfaces between the grommets and the conductors extending therethrough, and (iii) a continuous sidewall structure between the panel hole and conductor. In other words, when liquid-tight grommets are installed, due to a relatively large thickness dimension of the grommet circumferential sidewall, there is no discernable void space(s) between the conductors and grommets, or grommets and panel. In addition to the relatively thick circumferential sidewall, to achieve and maintain the liquid-tight functionality, such grommets are typically sized and configured so that they are held in a somewhat compressed state within the panel hole. This helps the liquid-tight grommet to squeeze downwardly on the conductors, ensuring a liquid tight seal between the grommet and conductor(s), and the grommet and panel.
Due to the thick sidewalls and somewhat inflexible characteristics of liquid-tight grommets, such grommets cannot be folded down but rather are forcefully inserted axially into panel holes. Accordingly, many liquid-tight grommets have a tapering or frusto-conical end that inserts through a panel hole first. In this configuration, as the grommet axially advances through the hole, an outer surface of the tapering end engages the perimeter edge of the hole. As it is pushed further through the hole, the tapering end is concentrically squeezed by the hole, momentarily reducing the outer diameter of the tapering end to the same dimension as the inner diameter of the hole. Such diameter reduction, which facilitates the grommet installation, is primarily a function of collapsing the axial throughbore of the grommet while the grommet is pushed or pulled through the hole. Since liquid-tight grommets tightly or snugly hold conductors in the axial throughbores, the grommet must be installed in the panel prior to the conductor. This is because a preinstalled conductor fills the throughbore in its entirety and therefore does not permit the throughbore to collapse as required for the grommet's installation into the panel. Since conductors cannot be preinstalled in liquid-tight grommets, a device incorporating liquid-tight grommets must be wired onsite where the panel is located. In other words, liquid tight grommets are typically installed in a panel before a wire or conductor is pulled through the grommet. This conventional method can be seen in FIG. 9, illustrating a liquid tight grommet “LTG” installed in a panel, before a conductor or wire “W” is routed through the liquid tight grommet “LTG.”
Notwithstanding, in light of the rapid globalization of manufacturing, it is often desirable to perform preassembly tasks, preinstall various components, and construct subassemblies, e.g., build wire harnesses, at locations that are geographically separated from a final assembly facility. More frequently now than ever, such separate facilities may be located in different countries. Factors such as labor costs, transportation infrastructure, facility operating costs, and others, influence which particular facilities are best suited for performing particular manufacturing and assembly processes and tasks. Frequently, it is cost effective to perform low-technology, low-skill processes and tasks, such as assembly of wire harnesses and grommets, at locations that are separate from final assembly facilities.
Despite best efforts, however, liquid-tight grommets cannot be preinstalled on conductors or wire harnesses at a facility other than the facility that has the corresponding panel in which the grommet will be mounted. This, at times, leads to grommet and wire harness assembly at economically inappropriate facilities, as well as increased final assembly times.